Abstract: The program is completed by FORTRAN, the geometrically nonlinear analysis of membrane structures is performed by using the spacial triangle membrane element with three node and nine freedom,and the pre-stress is considered with tangent stiffness matrix. The membrane can not resist compression stress, the constitutive matrix is modified considering tension theory to modify the stiffness matrix, and the wrinkling zone is obtained. The solution of the prestressed membrane in pure bending is well compared with the theory solution. Examples indicate the reliability of the program.

Key words: membrane structures, tension field, wrinkling, bifurcation buckling, constitutive matrix